Multiplex transmission system including sequenctial pulsing circuitry



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n @N E Wu. m OF WILQ United States Patent 3,395,250 MULTIPLEX TRANSMISSION SYSTEM INCLUDING SEQUENTIAL PULSING CIRCUITRY Dallas H. Lien, Indianapolis, Ind., assignor to Western Electric Company, Incorporated, New York, N.Y., a corporation of New York Original application May 2, 1962, Ser. No. 191,840, now Patent No. 3,280,335, dated Oct. 18, 1966. Divided and this application July 12, 1966, Ser. No. 574,518

24 Claims. (Cl. 179-15) The present application is a division of copending application Serial No. 191,840, filed May 2, 1962 now U.S. Patent No. 3,280,335, issued Oct. 18, 1966.

This invention relates to multiplex transmission systems including sequential pulsing circuitry, and more specifically to transmission systems for transforming a plurality of independent data bits from a plurality of independent data sources to a series of time related data bits which are transmitted over a single transmission line and for subsequently transforming the series of time related data bits into a plurality of independent data bits which are transmitted to a receiving circuit. Accordingly, objects of this invention are to provide new and improved transmission systems of such character.

In the transmission of data bits, it is often desirable to transform a plurality of independent data bits which are provided by a plurality of independent data sources into a series of time related data bits which may be transmitted over a single transmission line and then to transform the series of time related data bits into a plurality of independent data bits which may be transmitted to a plurality of independent receivers. Another object of this invention is to provide a transmission system which may be preconditioned to perform either of these functions.

Another object of this invention is to provide an improved transmission system for independently storing input data bits in a first plurality of memory devices while data bits previously stored in a second plurality of memory devices are sequentially read out to form a series of time related data bits.

An additional object of this invention is to provide an improved transmission system for sequentially storing a plurality of independent data bits in a first plurality of memory devices while data bits previously stored in a second plurality of memory devices are sequentially read out to form a series of time related data bits.

A further object of this invention is to provide an improved composite transmission system for sequentially reading out previously stored data bits from a plurality of transmission systems to form a series of time related data bits while data bits are being stored independently in each transmission system.

Still another object of this invention is to provide an improved transmission system for receiving a series of time related data bits and sequentially storing the time related data bits in a first plurality of memory devices while data bits previously stored in a second plurality of memory devices are independently read out.

An additional object of this invention is to provide an improved composite transmission system for receiving a series of time related data bits and sequentially storing the time related data bits in a plurality of transmission systems while previously stored data bits are being independently read out in each transmission system.

Another object of this invention is to provide a multiplex transmission system for multiplexing a plurality of unsynchronized data sources.

A still further object of this invention is to provide improved circuits for sequentially inducing flux change pulses in succeeding ones of a plurality of magnetic components, which sequential pulsing circuits are especially Patented July 30, 1968 ice useful as a part of the subject multiplex transmission systems.

With these and other objects in mind, the present invention relates primarily to a transmission system for transforming a plurality of independent data bits into a series of time related data bits. A plurality of data sources and a storing control circuit are alternately associated with two sets of a plurality of bistable memory devices while an output conductor and a read out control circuit are associated with the set of memory devices not associated with the data sources and the storing control circuit. The storing control circuit is responsive to input data bits produced by the data sources and causes selected memory devices within an associated set to be driven from primary stable states to secondary stable states to store data bits representative of the input data bits. The read out control circuit operates concomitantly with the storing control circuit and causes the memory devices within an associated set which have attained the secondary stable states to be sequentially driven to the primary stable states so that a series of time related data bits representative of previously stored data bits ate induced in the output conductor.

The present invention also relates to a transmission system for transforming a series of time related data bits into a plurality of independent data bits, which system is preferably utilized in conjunction with the transmission system for transforming the plurality of independent data bits into a series of time related data bits.

Additionally, the present invention also relates to apparatus for sequentially inducing flux change pulses in succeeding ones of a plurality of magnetic components, which apparatus is preferably utilized in conjunction with the transmission system for transforming the plurality of independent data bits into a series of time related data bits. The apparatus consists of a plurality of control windings having prescribed winding patterns to which are applied control signals having prescribed polarities, frequencies, and amplitudes.

Other objects, advantages, and features of the invention will become apparent by reference to the following detailed description and the accompanying drawings which illustrate preferred embodiments thereof, in which:

FIG. 1 depicts the manner in which FIGS. 1A and 1B are to be connected to form a schematic diagram of a multiplex transmission system illustrating a first embodiment of the invention;

FIG. 2 depicts the manner in which FIGS. 2A and 2B are to be connected to form a detached schematic diagram illustrating a winding pattern of a pair of control windings for controlling the storing and reading out operations of the multiplex transmission system illustrated in FIGS. 1A and 1B;

FIG. 3 is a block diagram illustrating the connections of a pluarility of transmitting and receiving multiplex transmission systems of a second embodiment of the invention to a single conductor;

FIG. 4 depicts the manner in which FIGS. 4A, 4B, and 4C are to be connected to form a schematic diagram of one of the transmitting multiplex transmission systems illustrated in block form in FIG. 3, illustrating a transmitting portion of a second embodiment of the invention;

FIG. 5 is a detached schematic diagram illustrating a winding pattern of three storing control windings for sequentially inducing flux change pulses in magnetic components of the multiplex transmission system illustrated in FIGS. 4A, 4B, and 4C;

FIG. 6 is a detached schematic diagram illustrating a second storing control winding embodiment for the multiplex transmission system illustrated in FIGS. 4A, 4B, and 4C, wherein three binary control windings are utilized;

FIG. 7 depicts the manner in which FIGS. 7A and 7B are to be connected to form a detached schematic diagram illustrating a third storing control winding embodiment for the multiplex transmission system illustrated in FIGS. 4A, 4B, and 4C, wherein a plurality of sinusoidal and cosinusoidal control windings are utilized;

FIG. 8 is an enlarged view of a flux change pulse induced in a magnetic component of the multiplex transmission system illustrated in FIGS. 4A, 4B, and 4C by the control winding embodiment illustrated in FIGS. 7A and 7B;

FIG. 9 is a table depicting the number of turns of read out control windings wound on read out reactor cores of all the transmitting multiplex transmission systems illustrated in block form in FIG. 3;

FIG. 10 depicts the manner in which FIGS. 10A and 10B are to be connected to form a schematic diagram of one of the receiving multiplex transmission systems illustrated in block form in FIG. 3, illustrating a receiving portion of the second embodiment of the invention; and

FIG. 11 is. a table depicting the eletcromagnetic association for read out of input reactor cores and memory devices of all the receiving multiplex transmission sys tems illustrated in block form in FIG. 3.

FIRST MULTIPLEX TRANSMISSION SYSTEM EMBODIMENT Referring now in detail to the drawings and more specifically of FIGS. 1A and 1B, a simplified form of a multiplex transmission system 10 is illustrated in accordance with a first embodiment of the invention. The multiplex transmission system 10 may be used either (1) to transform a plurality of independent binary digit data signals into a series of time related binary digit data signals or (2) to transform a series of time related binary digit data signals into a plurality of independent binary digit data signals. For brevity, the binary digit data signals will be referred to as data bits in the following description of the invention.

The manner in which the multiplex transmission system 10 functions when transforming a plurality of independent data bits into a series of time related data bits will first be described under the heading Parallel to Series Transformation and then the manner in which the multiplex transmission system 10 functions when transforming a series of time related data bits into a plurality of independent data bits will be described under the heading Series to Parallel Transformation.

Parallel to series transformation The multiplex transmission system 10 includes a plurality of ring type magnetic memory devices 11A-11F (FIG. 1A) and 12A-12F (FIG. 1B) which are composed of a material having a nearly rectangular hysteresis loop, such as magnesium-manganese ferrite, copper-manganese ferrite, or tape wound 4-79 Permalloy (1 mil or thinner tape; Permal-loy composition4 parts Mo, 79 parts Ni, remainder iron and impurities), so that each memory device has a primary stable state (negative saturation) and a secondary stable state (positive saturation). More specifically, the memory devices are bistable and are incapable of assuming any other states of magnetization. A memory device may be driven from one stable state to the other stable state only when an input magnetizing force is applied thereto which corresponds in amplitude to the coercive force of the memory device. A magnetizing force less than that required to drive a memory device from one stable state to the other stable state will urge the memory device toward the other stable state but will have no resultant efiect thereon and the memory device will remain in the original stable state. A flux change pulse is induced in a memory device only when the memory device is driven from one stable state to the other stable state.

Th memory devices. are divided into two sets of six memory devices 11A-11F and 12A-12F so that, during operation of the transmission system, six independent data sources and receivers 13A-13F, wherein input data bits are generated during the parallel to series transformation, are alternately associated electromagnetically with the two sets. of memory devices while an output conductor 14 (FIG. 1B) is associated electromagnetically with the set of memory devices not associated with the data sources and receivers, to permit data bits representative of input data bits to be stored in one set w-hile previously stored data bits are read out from the other set.

Each memory device 11A-11F and 12A-12F has an electrically independent input winding 15A15F and 16A16F wound thereon so as to be electromagnetically associated therewith and each input winding 15A-15F and 16A-16F has the same number of turns. During the first half of each cycle of operation, a switching circuit 26 (FIG. 1A) operates .to connect the input windings 15A15F on the memory devices 11A-11F in series with the data sources and receivers 13A-13F and, during the second half of each cycle of operation, the switching circuit 26 operates to connect the input windings 16A-16F on the memory devices 12A-12F in series with the data sources and receivers ISA-43F. The design and operation of the switching circuit 26 are set forth in detail hereinafter.

The memory device 11A-11F and 12A-12F are preconditioned so that, at the beginning of a transmission operation, they are all in the primary stable states. When one of the data sources and receivers ISA-13F is connected in series with one of the input windings within one of the groups ISA-15F or 16A-16F and an input data bit is generated in the data source and receiver, a positive magnetizing force is applied to the associated one of the memory devices within one of the sets 11A- 11F or 12A-12F and urges the memory device toward the secondary stable state. Input data bits may be generated in selected ones of the data sources and receivers 13A13F so that magnetizing forces are applied only to selected ones of the associated memory devices 11A-11F or 12A-12F, and the input data bits generated in the data sources and receivers 13A-13F are limited in amplitudes so that the magnetizing forces applied thereto which act upon the associated memory devices 11A-11F or 12A- 12F do not have suificient amplitudes to drive the memory devices from the primary stable states to the secondary stable states.

Since the selected memory devices must be driven from the primary stable states to the secondary stable states to store data bits representative of the input data bits generated by selected ones of the data sources and receivers 13A-13F, additional positive magnetizing forces must be applied to the selected memory devices which combine with the positive magnetizing forces applied thereto by the input data bits to drive the selected memory devices to the secondary stable states. A pair of control windings 17 and 18 are wound about the memory devices 11A11F and 12A-12F so as to be electromagnetically associated therewith and control signals are applied to the control windings 17 and 18 from a pair of control signal generators 19 and 20 (FIG. 1A) to provide the additional magnetizing forces required to drive the selected memory devices to the secondary stable states.

The control windings 17 and 18 have periodic characteristics variations in the winding patterns which are distinct from but bear a predetermined relationship to each other so that a different combination of winding patterns of the control windings is established on each of the memory devices 11A-11F nad 12A12F. The control signals generated by the control signal generators 19 and 20 and applied to the control windings 17 and 18 have polarities, frequencies, and amplitudes which are determined by the winding patterns so that (1) during the first half of each cycle of operation, maximum positive magnetizing forces are sequentially applied thereby to succeeding ones of the memory devices 11A-11F while maximum negative magnetizing forces are sequentially applied thereby to succeeding .ones of the memory devices 12A 12F (some of which have attained the secondary stable states); and (2) during the second half of each cycle of operation, maximum positive magnetizing forces are sequentially applied thereby to succeeding ones of the memory devices 12A12F while maximum negative magnetizing forces are sequentially applied thereby to succeeding ones of the memory devices 11A-11F (some of which have attained the secondary stable states).

The control signal amplitudes are so selected that the maximum magnetizing forces applied thereby to the memory devices do not have suflicient amplitudes to drive the memory devices from one stable state to the other stable state. However, the amplitudes of the input data bits and the control signals are so selected that the cumulative effects of the positive magnetizing forces produced by the input data bits and the maximum positive magnetizing forces produced by the control signals are sufficient in amplitude to drive the selected memory devices from the primary stable states to the secondary stable states.

Thus, during the first half of each cycle of operation, selected ones of the memory devices 11A-11F which have magnetizing forces applied thereto by input data bits are sequentially driven from the primary stable states to the secondary stable states to store data bits representative of the input data bits and, during the second half of each cycle of operation, selected ones of the memory devices 12A-12F which have magnetizing forces applied thereto by input data bits are sequentially driven from the primary stable states to the secondary stable states to store data bits representative of the input data bits.

Each memory device 11A-11F and 12A-12F also has (1) a bias winding 21A-21F and ZZA-ZZF and (2) an output winding 23A23F and 24A-24F wound thereon so as to be electromagnetically associated therewith. Each of the bias windings has the same number of turns and each of the output windings has the same number of turns. The bias windings 21A-21F are connected to form a series arrangement, the bias windings 22A22F are connected to form a series arrangement, the output windings 23A- 23F are connected to form a series arrangement, and the output windings 24A-24F are connected to form a series arrangement.

During the first half of each cycle of operation, the previously mentioned switching circuit 26 operates to connect the series arrangement of the output windings 24A- ME in series with the output conductor 14 and, during the second half of each cycle of operation, the switching circuit 26 operates to connect the series arrangement of the output windings 23A23F in series with the output conductor 14.

A biasing and switching signal generator 25 (FIG. 1A) is provided for generating a square wave output signal which acts as both a biasing signal and a switching signal during the parallel to series transformation. A second generator 27 (FIG. 1A) is utilized only during the series to parallel transformation to be described hereinafter, and may be disregarded for the present description. The biasing and switching signal generator 25 is connected to the series arrangements of the bias windings 21A21F and 22A-22F through a pair of diodes D1 and D2 and is connected directly to the switching circuit 26 as set forth below. A center ground resistor CGR is connected across output terminals 25A and 25B of the biasing and switching signal generator 25 so that (1) when the output thereof has a positive polarity, the first terminal 25A is positive and the second terminal 258 is negative and (2) when the output thereof has a negative polarity, the first terminal 25A is negative and the second terminal 25B is positive.

The biasing and switching signal generator 25 is operated in timed relationship with respect to the control signal generators 19 and 20 so that, during the first half of each cycle of operation, the output thereof has a negative polarity and, during the second half of each cycle of operation, the output thereof has a positive polarity. The diodes D1 and D2 are so arranged that, when the output signal of the biasing and switching signal generator has a negative polarity and the first terminal 25A is negative, a biasing signal is applied to the series arrangement of the bias windings 22A-22F and, when the output signal of the biasing and switching signal generator has a positive polarity and the second terminal 253 is negative, a biasing signal is applied to the series arrangement of the bias windings 21A-21F. Negative magnetizing forces are applied to the associated memory devices 11A-11F or 12A- 12F which have attained the secondary stable states, when the biasing signal is applied to the bias windings 21A-21F or 22A22F, and the negative magnetizing forces urge the memory devices toward the primary stable states.

The biasing signal generated by the biasing and switching signal generator 25 has a limited amplitude so that magnetizing forces applied to the associated memory devices 11A11F or 12A-12F which have assumed the secondary stable states do not have sufficient amplitudes to drive the memory devices to the primary stable states. However, the amplitude of the biasing signal is so selected that the cumulative effects of the negative magnetizing forces produced by the biasing signal and the maximum negative magnetizing forces produced by the control signals, as discussed previously, are sufficient in amplitude to drive the memory devices from the secondary stable states to the primary stable states.

Thus, during the first half of each cycle of operation, negative magnetizing forces are applied to the memory devices 12A-12F which have attained the secondary stable states by the biasing signal and maximum negative magnetizing forces are sequentially applied to succeeding ones of the memory devices 12A12F by the control signals so that the memory devices 12A-12F which have attained the secondary stable states are sequentially driven to the primary stable states and flux change pulses are induced therein. Since the series arrangement of the output windings 24A-24F on the memory devices 12A-12F is connected in series with the output conductor 14 during the first half of each cycle of operation, a series of time related output data bits representative of the stored data bits are sequentially induced in the output conductor 14 by the flux change pulses induced in the memory devices.

During the second half of each cycle of operation, negative magnetizing forces are applied to the memory devices 11A-11F by the biasing signal and maximum negative magnetizing forces are sequentially applied to succeeding ones of the memory devices 11A-11F by the control signals so that the memory devices 11A-11F which have attained the secondary stable states are sequentially driven to the primary stable states and flux change pulses are induced therein. Since the series arrangement of the output windings 23A-23F of the memory devices 11A11F is connected in series with the output conductor 14 during the second half of each cycle of operation, a series of time related output data bits representative of the stored data bits is induced in the output conductor 14 by the flux change pulses induced in the memory devices.

Each series of time related output data bits induced in the output conductor 14 by operation of the transmission system 10 may be transmitted over the output conductor 14 to a similar multiplex transmission system wherein they are transformed from a series of time related data bits to a plurality of independent data bits which are transmitted to a plurality of independent data sources and receivers that are then used as receivers. The utilization of the transmission system 10 for receiving a series of time related data bits and transforming them into a plurality of independent data bits is set forth below under the heading Series to Parallel Transformation.

Switching circuit 26 The above-mentioned switching circuit 26 (FIG. 1A)

is provided to perform the necessary switching operations for the transmission system 10. The switching circuit operates in response to the output of the biasing and switching signal generator 25 and since the biasing and switching signal generator 25 is operated in timed relationship with respect to the control signal generators 19 and 20, the switching circuit 26 is operated in timed relationship with respect to the outputs of the control signal generators.

During the first half of each cycle of operation, the switching circuit 26 operates in response to the negative output signal of the biasing and switching signal generator 25 1) to connect the data sources and receivers 13A- 13F in series with the input windings ISA-F on the memory devices 11A-11F and (2) to connect the output conductor 14 in series with the series arrangement of the output windings 24A-24F on the memory devices 12A- 12F. During the second half of each cycle of operation, the switching circuit 26 operates in response to the positive output of the biasing and switching signal generator (1) to connect the data sources and receivers 13A-13F in series with the input windings 16A16F on the memory devices 12A-12F and (2) to connect the output conductor 14 in series with the series arrangement of the output windings 23A-23F on the memory devices 11A-11F.

The switching circuit 26 includes four transistors T1- T4. Two of the transistors T1 and T2 operate as output ground switches for connecting one of the series arrangements of output windings 23A-23F or 24A-24F in series with the output conductor 14, and two of the transistors T3 and T4 operate as input ground switches for connecting the input windings ISA-15F or 16A16F in series with the data sources and receivers 13A-13F.

The emitters of all the transistors T1-T4 are connected to ground, the collector of the transistor T1 is connected to one side of the series arrangement of the output windings 23A-23F, the collector of the transistor T2 is connected to one side of the series arrangement of the output windings 24A-24F, the collector of the transistor T3 is connected to one side of all the input windings ISA-15F, and the collector of the transistor T4 is connected to one side of all the input windings 16A-16F.

The bases of the transistors T2 and T3 are connected together and are connected to the second output terminal 25B of the biasing and switching signal generator 25 so that, when the output of the biasing and switching signal generator 25 is negative, during the first half of each cycle of operation, the terminal 25B is positive and the transistors T2 and T3 conduct (1) to complete the series connection between the output conductor 14 and the series arrangement of the output windings 24A-24F and (2) to complete the series connection between the data sources and receivers 13A-13F and the input windings ISA-15F. The bases of the transistors T1 and T4 are connected together and are connected to the first output terminal 25A of the biasing and switching signal generator 25 so that, when the output of the biasing and switching signal generator 25 is positive, during the second half of each cycle of operation, the terminal 25A is positive and the transistors T1 and T4 conduct 1) to complete the series connection between the output conductor 14 and the series arrangement of the output windings 23A-23F and (2) to complete the series connection between the data sources and receivers 13A-13F and the input windings 16A-16F.

Control windings 17 and 18 The control windings 17 and 18 are illustrated in detached side-by-side relationship in FIGS. 2A and 2B so that the operation of the invention may be depicted more clearly. As illustrated, the control windings have periodic characteristic variations so that a, different combination of winding patterns of the control windings is established on each of the memory devices 11A-11F and 12A12F.

The first control winding 17 is wound on the memory devices in a sinusoidal winding pattern so that the numher of turns N wound on each memory device is determined by the following equation:

N max sin 21rx/ 11:6 sin 0 wherein N, is an arbitrary constant designating the maximum number of turns (chosen as 6 in the illustrated embodiment), x is the number of the particular memory device (the memory devices being sequentially numbered from 0 to 11 so that the memory devices 11A-11F are numbered from 0 to 5 and the memory devices 12A-12F are numbered from 6 to 11), n is the total number of memory devices (chosen as 12 in the illustrated embodimerit), and 0 is substituted for 21rx/n and is the angular interval for the particular memory device (substituting in values of x and n, 0 varies in 30 intervals from 0 to 330).

By solving the equation set forth above for the sine control winding 17, the number of turns of the sine control winding 17 associated with the memory device 11A is 0 turns since N 6 sin 0 and the sine of 0 is 0. The number of turns of the sine control winding 17 associated with the memory device 11B is three turns in the first hand or positive direction since N -=6 sin 30 and the sine of 30 is .5. Similarly, the number of turns of the sine control winding associated with each succeeding memory device 11C-11F and 12A-12F may be determined by solving the above-mentioned equation so that the number of turns set forth in FIGS. 2A and 2B are provided.

The second control winding 18 is wound on the memory device in a cosinusoidal winding pattern so that the number of turns N wound on each memory device is determined by the following equation:

By solving this equation for the cosine control winding 18, the number of turns of the cosine control winding 18 associated with the memory device 11A is six turns in the first hand or positive direction since N=6 cos 0 and the cosine of 0 is 1. The number of turns of the cosine control winding 18 associated with the memory device 11B is approximately 5.2 turns in the first hand or positive direction since N=6 cos 30 and the cosine of 30 is 0.866. Similarly, the number of turns of the cosine control winding associated with each succeeding memory device 11C-11F and 12A-12F may be determined by solving the above-mentioned equation so that the number of turns set forth in FIGS. 2A and 2B are provided.

The pair of control signal generators 19 and 20 apply control signals to the control windings 17 and 18 which also vary according to sinusoidal and cosinusoidal functions. The first control signal generator 19 applies a sinusoidal control signal to the sinusoidal control winding 17 which varies according to the equation I =l sin 21rft=sin left and the second control signal generator 20 applies a consinusoidal control signal to the consinusoidal control winding 18 which varies according to the equation cos max COS f =COS 21ft wherein ;f is frequency, t is time, and I is an arbitrary constant designated as the maximum value of the control signals generated by the control signal generators 19 and 20 (chosen as 1 in the illustrated embodiment).

The magnetizing energy H supplied to a memory device by applying the sine control signal to the sine control winding 17 is determined by the following equation:

sin ain) sin) rnax Sin 1 rnax Sin 2.\'/Il)-*:(slt1 21rf!) (6 sin ZmY/lZ) and the magnetizing energy H supplied to a memory device by applying the cosine control to the cosine control winding, 18 is determined by the following equation:

oes oos) cos) max cos E) m'ax cos 21rx/n) =(cos 21rfl) (6 cos 21rx/12) Therefore, the total magnetizing energy supplied to a memory device at any given time is determined by the following equation:

H =(sin 21r7t) (6 sin 21rx/l2) +cos 21rft) (6 cos 21rx/l2) and this equation may be solved by the trigonometric identity cos (A'B)=sin A sin B+cos A cos B so that tota1= cos [21r(x/12.

The above total magnetizing energy equation illustrates that the total magnetizing energy is'a maximum when (x/12ft) =0, 1, 2, 3 Since time moves forward at a constant rate, the maximum magnetizing energy sequentially shifts from one memory device to the next at a constant rate. It should also be noted that maximum positive magnetizing energy and a maximum negative magnetizing energy are provided by the total magnetizing energy equation since the equation varies according to a cosine function and the above total magnetizing energy cosine function 6 cos [21r(x/l2-;ft)] has a maximum positive value when 21r(x/12ft) equals an even integral multiple of 1r and has a maximum negative value when 21r(x/12ft) equals an odd integral multiple of 11'. The maximum magnetizing energies are 1r (or 180) out of phase with respect to each other so that while one memory device has a maximum positive magnetizing force applied thereto by the maximum positive magnetizing energy, another memory device, six intervals removed therefrom, has a maximum negative magnetizing force applied thereto by the maximum negative magnetizing energy.

The relationship of the maximum magnetizing energies with respect to the memory devices 11A11F and 12A- 12F is illustrated in FIGS. 2A and 23 as the value of 21rft is varied in 1r/6 (or 30) intervals between 01r and 111r/ 6. As previously set forth, the magnetizing energy induced by applying the sine control signal to the sine control winding 17 is equal to (N (sin 21rft) and the magnetizing energy induced by applying the cosine control signal to the cosine control winding 18 is equal to (N (cos 21rft). In the illustrated example, the maximum cumulative magnetizing energies are equal to 6 and the mathematical solutions for the sequential inducing thereof are set forth below.

When 21rft=01r or (1) the energy induced adjacent the memory device 11A has a maximum positive value since H =6 cos 0=6 1=+6 and so that H =6+0=+6 and (2) the energy induced adjacent the memory device 12A has a maximum negative value since H =-6 cos O=6 l=6 and so that H =(6)+(0)=6. When 21rft=(1r/6) or (30): (1) the energy induced adjacent the memory device 11B has a maximum positive value since and (2) the energy induced adjacent the memory device 12B has a maximum negative value since Similarly, as 21rft increases in 7r/ 6 or 30 intervals, the maximum positive and negative magnetizing energies are sequentially induced adjacent succeeding ones of the memory devices 11A-11F and 12A-12F. Maximum negative magnetizing energies are sequentially induced adjacent succeeding ones of the memory devices 12A12F as maximum positive magnetizing energies are sequentially induced adjacent succeeding ones of the memory devices 11A-11F and vice versa.

The control windings 17 and 18 are so wound that only the maximum positive magnetizing forces produced by applying the control signals to the control windings have sufficient amplitudes to combine with magnetizing forces produced by input data bits to drive selected ones of the memory devices 11A-11F and 12A-12F from the primary stable states to the secondary stable states so that flux change pulses are induced therein and that only the maximum negative magnetizing forces produced by applying the control signals to the control windings have sufiicient amplitudes when combined with the magnetizing forces produced by the biasing signal to drive the memory devices 11A-11F and 12A-12F which have assumed the secondary stable states to the primary stable states so that fiux change pulses are induced therein.

During the first half of each cycle of operation, maximum positive magnetizing forces are sequentially applied to the memory devices 11A-11F by the control signals which combine with magnetizing forces applied to selected ones of the memory devices 11A-11F by input data bits to sequentially drive the selected memory devices from the primary stable states to the secondary stable states. Also, during the first half of each cycle of operation, maximum negative magnetizing forces are sequentially applied to the memory devices 12A-12F and the maximum negative magnetizing forces combine with the negative magnetizing forces applied thereto by the biasing signal to sequentially drive the memory devices 12A-12F which have attained the secondary stable states to the primary stable states.

During the second half of each cycle of operation, maximum positive magnetizing forces are sequentially applied to the memory devices 12A-12F by the control signals which combine with magnetizing forces applied to selected ones of the memory devices 12A-12F by input data bits to sequentially drive the selected memory devices from the primary stable states to the secondary stable states. Also, during the second half of each cycle of operation, maximum negative magnetizing forces are sequentially applied to the memory devices 11A-11F and the maximum negative magnetizing forces combine with the negative magnetizing forces applied thereto by the biasing signal to sequentially drive the memory devices 11A-11F which have attained the secondary stable states to the primary stable states.

Series to parallel transformation During series to parallel transformation, the multiplex transmission system 10 (FIGS. 1A andlB) operates similarly to its operation during parallel to series transformation. However, the transmission system 10 must be conditioned for series to parallel transformation by energizing a pair of relays R1 and R2 (FIG. 1A). The relays R1 and R2 are energized by closing a switch SW1 so that the DC energizing potential from the source 28 is applied to the relays.

When relay R1 is energized, the contact arms RlA and RIB are moved from the primary contact terminals to the secondary contact terminals so that the previously mentioned biasing and switching signal generator 27 is connected in the transmission system 10 in place of the biasing and switching signal generator 25. The output signal generated by the biasing and switching signal generator 27 is one-half cycle out of phase with respect to the output signal generated by the biasing and switching generator 25 so that, during series to parallel transformation, the 

1. A MULTIPLEX TRANSMISSION SYSTEM FOR TRANSMITTING BINARY DIGIT DATA SIGNALS IN A SINGLE OUTPUT CONDUCTOR, WHICH COMPRISES: A PLURALITY OF DATA SOURCES; TWO SETS OF BISTABLE MEMORY DEVICES, EACH SET INCLUDING A PLURALITY OF MEMORY DEVICES EQUAL IN NUMBER TO THE NUMBER OF DATA SOURCES; STORING CONTROL MEANS RESPONSIVE TO INPUT DATA BITS PRODUCED BY THE DATA SOURCES FOR CAUSING SELECTED MEMORY DEVICES WITHIN A SELECTED SET OF MEMORY DEVICES TO BE DRIVEN FROM PRIMARY STABLE STATES TO SECONDARY STABLE STATES TO STORE DATA BITS REPRESENTATIVE OF THE INPUT DATA BITS THEREIN; READ OUT CONTROL MEANS OPERATING CONCOMITANTLY WITH THE STORING CONTROL MEANS FOR CAUSING SUCCEEDING ONES OF THE MEMORY DEVICES WITHIN A SELECTED SET OF MEMORY DEVICES THAT HAVE ATTAINED THE SECONDARY STABLE STATES TO BE SEQUENTIALLY DRIVE TO THE PRIMARY STABLE STATES SO THAT A SERIES OF TIME RELATED DATA BITS REPRESENTATIVE OF PREVIOUSLY STORED DATA BITS ARE INDUCED IN THE OUTPUT CONDUCTOR; AND 